sop/pd/315 01 standard operating procedure · university of malta faculty of medicine & surgery...

UNIVERSITY OF MALTA

FACULTY OF MEDICINE & SURGERY

PHARMACY DEPARTMENT Ref. No. SOP/PD/315_01

STANDARD OPERATING PROCEDURE

AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

Table of Contents

Page

1. Scope 2

2. Objective 2

3. Definitions 2

4. Responsibility 3

5. Procedure 3

6. Precautions 12

7. References 12

8. Appendices 12

9. Revision History 12

Original

Authorised Copy

for:

Reading Copy

Written by: Signature/Date:

Reviewed by: Signature/Date:

Approved by: Signature/Date:

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

1. Scope

This Standard Operating Procedure (SOP) applies to the staff and students

using the AA® Series AA-160 Precision Balance in the laboratories of the

Pharmacy Department, University of Malta.

2. Objective

To describe the procedure for the installation, configuration, operation,

calibration, maintenance and troubleshooting of the AA® Series AA-160

Precision Balance.

3. Definitions

3.1. Adjustable Feet: Circular screws situated at the bottom of the balance

that are manipulated to level the balance out.

3.2. Auto CAL Key: To initiate automatic calibration using internal

weights.

3.3. Calibration: A procedure to check a measuring instrument against an

accurate standard to determine any deviations and correct for errors.

3.4. Calibration Variance: The corrections made to the calibration values

to compensate for differences between the actual weight being used

and the desired value.

3.5. Configuration Parameters Set-Up Menu: Allows the user to adapt

the balance to different weighing situations (see SOP/PD/315_01/A1).

3.6. Message Display: Part of the dual LCD display that uses text to

provide additional information.

3.7. Number Display: Part of the dual LCD display that continuously

shows the weighing results.

3.8. On/Off Key: To turn the display ON or OFF or to enter the desired

option in the Set-Up menu.

3.9. Print Key: To transmit sample weight to printer or computer. Is also

used to scroll through the different options in the Set-Up Print menu.

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

3.10. Select Key: To scroll through the configuration parameters of a

particular option in the Configuration Parameters Set-Up menu.

3.11. Set-Up Key: To access the Configuration Parameters Set-Up menu and

then to cycle through its options. Is also used to access the Set-Up Print

menu.

3.12. Tare: Allows the balance to display the weight of the sample only and

not the combined weight of the sample and its container.

3.13. Tare Key: To set the Numeric Display to zero. Is also used to exit Set-

Up menu and return the balance to normal weighing mode.

3.14. U symbol: An unstable indicator that is automatically displayed

whenever the balance is not stable and then disappears when the

balance becomes stable.

3.15. Weighing Pan: The area on top of which the material to be weighed is

placed.

4. Responsibility

4.1. The members of the Department of Pharmacy (staff and students) are

responsible for following this SOP.

4.2. The designated Laboratory Officer or Laboratory Assistant is

responsible for ensuring that this SOP is followed.

5. Procedure

5.1. Installation

5.1.1. Place the balance on a stable surface, away from any vibrations.

5.1.2. Turn the adjustable feet at the bottom of the balance clockwise

or anticlockwise until the air bubble in the spirit level is in the

centre of the marked circle.

5.1.3. Insert power supply connector in the plug on the rear of the

balance and plug the power supply into the mains supply.

5.1.4. Press the On/Off key to switch on the balance.

5.1.5. Wait until the start-up message and then 0.0000 are displayed

before starting to operate the balance.

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.2. Configuration

5.2.1. Press the Set-Up key briefly but repeatedly until the desired

option is displayed (see SOP/PD/315_01/A1 – Configuration

Parameters Set-Up Table).

5.2.2. Press the On/Off key to enter into the desired option.

5.2.3. Press the SELECT key briefly but repeatedly until the desired

configuration parameter is displayed.

5.2.4. Press the TARE key to save changes and return the balance to

normal weighing mode.

5.3. Operation

5.3.1. Place the material that needs to be weighed on the weighing

pan.

5.3.2. Close the draft shield.

5.3.3. Wait until the [U] symbol disappears.

5.3.4. Read off the value from the display.

If using the tare function:

5.3.5. Place an empty weighing container on the weighing pan.

5.3.6. Close the draft shield.


5.3.8. Press the Tare key.

5.3.9. Open draft shield and place the material to be weighed in the

weighing container.

5.3.10. Close draft shield.


5.3.12. Read off the value from the display.

5.4. Calibration

5.4.1. Auto Calibration

5.4.1.1. Press the On/Off Key to switch on the balance.

5.4.1.2. Wait until the [U] symbol disappears from the

message display.

5.4.1.3. Press the TARE key.

5.4.1.4. Press the AUTO CAL key.

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.4.1.5. Wait until the message display changes from [CAL]

to [CAL-100-*] to [TARING] and finally to

[GRAMS] to indicate that the auto-calibration

process is complete.

5.4.2. External Calibration

5.4.2.1. Press the On/Off Key to switch on the balance.

5.4.2.2. Wait until the [U] symbol disappears from the

message display.

5.4.2.3. Press the TARE key.

5.4.2.4. Place the standard calibration weight on the

weighing pan.

5.4.2.5. Wait for the [U] symbol to disappear and the

calibration weight value together with [GRAM] to be

displayed.

5.4.2.6. Press the AUTO CAL key.

5.4.2.7. Wait until [XXX.0000] and [CAL-XXX-] are

displayed.

5.4.2.8. Remove the standard weight.

5.4.2.9. Perform the calibration procedure once again if it is

to be repeated with a different standard weight.

5.4.2.10. See SOP/PD/315_01/A2 – Calibration Variance

Table if calibration variance needs to be modified.

5.5. Maintenance

5.5.1. Disconnect the balance from its power supply before

attempting to clean and leave it in its normal operating position.

5.5.2. Use a clean fine brush to remove any surrounding powder.

5.5.3. Use a moistened cloth with a mild cleaning agent to clean and

remove any spilt material.

5.5.4. Ensure that the air bubble in the spirit level on the front end of

the scale is in the centre of the marked circle.

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.6. Troubleshooting

Fault Possible Cause/s Possible Solution/s

Both displays are blank

- Display previously turned off by the On/Off key

- Power cord not connected properly

- Power cut or an improper

voltage supply present

- Temporary fault

- Press the On/Off Key

- Attach the power cord accordingly

- Check if a proper power

supply is present

- Disconnect power cord, wait

for at least 5 seconds and reconnect

[OVER] is displayed Exceeded weighing capacity Reduce the weight

[UNDER] is displayed

- Pan is not properly

installed

- Pan is obstructed

- Install pan properly

- Move balance to a better

location

[GRAM U] continues to be

displayed

- Air currents present around balance

- Sample not stationary

- Move balance to a better location or close all draft

shields

- Ensure sample is made

stationary

[NO CAL] is displayed

during calibration process

Balance capacity is exceeded Use a 50g, 100g or 150g

standard calibration weight to complete calibration

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.7. Flow Charts

5.7.1. Installation

Start

Place balance on a stable surface,

away from any vibrations

Turn adjustable feet until air bubble

in spirit level is in the centre of the marked circle

Insert power supply connector in

the plug on rear of balance and plug power supply into mains supply

Press On/Off key to switch on balance

Wait until start-up message and 0.0000 are displayed before use

End

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.7.2. Configuration

Start

Press Set-Up key briefly but repeatedly

until desired option is displayed (see SOP/PD/315_01/A1)

Press On/Off key to enter desired option

Press SELECT key briefly but

repeatedly until desired configuration

parameter is displayed

Press TARE key to save changes and return

balance to normal weighing mode

End

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.7.3. Operation

Start

Place empty weighing container on weighing pan

Using tare function

Close draft shield

Wait until [U] symbol disappears

Open draft shield and place material to be

weighed in weighing container

Close draft shield


Read off value from display

End

Place material on weighing pan

Yes

No

Press Tare Key

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.7.4. Calibration

Start



Press TARE Key

Performing external

calibration

Place standard weight on weighing pan

Wait for [U] to disappear and

calibration weight value together

with [GRAM] to be displayed

Press AUTO CAL key

Wait until [XXX.000] and

[CAL-XXX-] are displayed

Remove standard weight

Repeat calibration

with different

standard weight End

Perform auto calibration by

pressing the AUTO CAL key

Wait until message display changes

from [CAL] to [CAL-100-*-] to

[TARING] and finally to [GRAMS]

No

No

Yes

Yes

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

5.7.5. Maintenance

Start

Balance needs

cleaning

Disconnect balance from power supply

Leave balance in its normal operating position and do not tilt sideways

Remove using a clean fine brush

Any surrounding

powder

Any spilt material

Remove using a moistened cloth

with a mild cleaning agent

Air bubble in spirit

level is in centre of

marked circle

End

Manipulate adjustable feet

until this is achieved

No

No

No

No

Yes

Yes

Yes

Yes

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

6. Precautions

6.1. Do not install balance near extremes of heat and cold.

6.2. Protect balance from dust and air draughts.

6.3. Keep weighing pan clean and dry to prevent inaccuracies.

6.4. Do not move balance during weighing.

6.5. Ensure that the maximum tolerated weight of 160g is not exceeded

during weighing procedures and also when using the tare function.

6.6. Do not leave any items on the balance when this is not in use.

6.7. Only use the balance if the spirit level is correct.

6.8. Adjust the air bubble in the spirit level each time the balance is moved

to a different location.

6.9. Avoid static charge buildup of the material to be weighed and of the

weighing container.

6.10. When transferring balance to a significantly warmer environment,

allow it to acclimatise for approximately 2 hours at room temperature

after it has been disconnected from the mains.

6.11. Do not unplug balance as this is designed to be continuously plugged

in.

6.12. Ensure that an audible beep is heard whenever one of the keys is

pressed if the beeper option is activated. If this beep is not heard, press

the key again until the beep is heard.

7. References

Denver Instrument Company. AA® Series Electronic Analytical Balances

Operating Instructions.

8. Appendices

SOP/PD/315_01/A1 – Configuration Parameters Set-Up Table

SOP/PD/315_01/A2 – Calibration Variance Table

9. Revision History

Version Number Amendments/ Reasons for change

01 Initial Release

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

SOP/PD/315_01/A1 – Configuration Parameters Set-Up Table

Option Function

CURRENT To display the current selected configuration parameters

DEFAULT To reset the balance to the default factory configuration

parameters

FILTER

To choose the desired filter settings from [FT FAST] in

ideal conditions, [FT NORMAL] in standard laboratory

conditions and [FT SLOW] in areas with drafts and

vibrations

AUTO ZERO To choose to automatically compensate for zero drift [A-Z ON] or to turn off this correction feature [A-Z OFF]

BEEPER

To choose between short beeps [BP SHORT], long beeps

[BP LONG] or else to turn off the beeper function [BP

OFF]

UNIVERSITY OF MALTA




AA®

SERIES AA-160

PRECISION BALANCE

Valid for:

2 years from

approval

of 14

SOP/PD/315_01/A2 – Calibration Variance Table

Procedure Message Display


Press AUTO CAL key CAL

Press SET UP key repeatedly until calibration value to

be modified is displayed for e.g. for 100g CAL-100-

Press On/Off key V + 00.0

Press SELECT key repeatedly until desired + or – sign is

displayed V + 00.0 or V – 00.0

Press On/Off key

Press SELECT key repeatedly to change first digit

(between 0 and 1) V +/- x0.0

Press On/Off key when desired digit is displayed

Press SELECT key repeatedly to change next digit (between 0 and 9)

V +/- 1x.0

Press On/Off key when desired digit is displayed

Repeat the last 4 steps for subsequent digits

sop/pd/315 01 standard operating procedure · university of malta faculty of medicine & surgery...

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